reinstate base path handling

packages/kit/src/exports/vite/dev/index.js

@@ -13,6 +13,7 @@ import { SVELTE_KIT_ASSETS } from '../../../constants.js';
 import * as sync from '../../../core/sync/sync.js';
 import { get_mime_lookup, runtime_base, runtime_prefix } from '../../../core/utils.js';
 import { compact } from '../../../utils/array.js';
+import { not_found } from '../utils.js';
 
 const cwd = process.cwd();
 
@@ -318,6 +319,10 @@ export async function dev(vite, vite_config, svelte_config) {
 					return;
 				}
 
+				if (!decoded.startsWith(svelte_config.kit.paths.base)) {
+					return not_found(req, res, svelte_config.kit.paths.base);
+				}
+
 				if (decoded === svelte_config.kit.paths.base + '/service-worker.js') {
 					const resolved = resolve_entry(svelte_config.kit.files.serviceWorker);
 

packages/kit/src/exports/vite/index.js

@@ -237,7 +237,7 @@ function kit() {
 			/** @type {import('vite').UserConfig} */
 			const result = {
 				appType: 'custom',
-				base: svelte_config.kit.paths.base,
+				base: './',
 				build: {
 					rollupOptions: {
 						// Vite dependency crawler needs an explicit JS entry point

packages/kit/src/exports/vite/preview/index.js

@@ -6,6 +6,7 @@ import { getRequest, setResponse } from '../../../exports/node/index.js';
 import { installPolyfills } from '../../../exports/node/polyfills.js';
 import { SVELTE_KIT_ASSETS } from '../../../constants.js';
 import { loadEnv, normalizePath } from 'vite';
+import { not_found } from '../utils.js';
 
 /** @typedef {import('http').IncomingMessage} Req */
 /** @typedef {import('http').ServerResponse} Res */
@@ -73,11 +74,7 @@ export async function preview(vite, vite_config, svelte_config) {
 				next();
 			} else {
 				res.statusCode = 404;
-				res.end(
-					`The server is configured with a public base URL of ${base} - did you mean to visit <a href="${
-						base + pathname
-					}">${base + pathname}</a> instead?`
-				);
+				not_found(req, res, base);
 			}
 		});
 

packages/kit/src/exports/vite/utils.js

@@ -2,6 +2,7 @@ import path from 'path';
 import { loadConfigFromFile, loadEnv, mergeConfig } from 'vite';
 import { runtime_directory } from '../../core/utils.js';
 import { posixify } from '../../utils/filesystem.js';
+import { negotiate } from '../../utils/http.js';
 
 /**
  * @param {import('vite').ResolvedConfig} config
@@ -149,3 +150,31 @@ export function get_env(env_config, mode) {
 		private: Object.fromEntries(entries.filter(([k]) => !k.startsWith(env_config.publicPrefix)))
 	};
 }
+
+/**
+ * @param {import('http').IncomingMessage} req
+ * @param {import('http').ServerResponse} res
+ * @param {string} base
+ */
+export function not_found(req, res, base) {
+	const type = negotiate(req.headers.accept ?? '*', ['text/plain', 'text/html']);
+
+	// special case — handle `/` request automatically
+	if (req.url === '/' && type === 'text/html') {
+		res.statusCode = 307;
+		res.setHeader('location', base);
+		res.end();
+		return;
+	}
+
+	res.statusCode = 404;
+
+	const prefixed = base + req.url;
+
+	if (type === 'text/html') {
+		res.setHeader('Content-Type', 'text/html');
+		res.end(`Not found (did you mean <a href="${prefixed}">${prefixed}</a>?)`);
+	} else {
+		res.end(`Not found (did you mean ${prefixed}?)`);
+	}
+}